Coating damp or wet stone



Patented Sept. 29, 1931 p TED iSTATE SAMUEL. s. Swinge cr rls'rnur mLnsrnmcrrntn 'rownsnir, momrcomnniz COUNTY, BENNSYLVANIA,.ASSIGNOR T AIVIIESITE ASPHALT COMPANY OF AMERICA,

OE PHILADELPHIA, PENNSYLVANIA, A CORPORATION NEIV JERSEY COATING DAMP on war STONE No Drawing."

This invention relates to improvements in 5 stituting the aggregate of which the road out the'use of on thesurfaces of the stone.

composition'is made, with asphalt or other bitumen. a i

It is frequently'desirable to make road ways of the general typeset forth in U. S. Patent No. 1,611,444 without special drying of the'stone or the aggregate inpreparation for coating the stone with bitumen." Difi'i-, iculty, however,'has-been experienced in the absence ofrthe drying operationof obtain- 'ing a satisfactory bond betweenthe bitumen and the surfaces of the'ston'e. It has been particularly difiicult to obtain satisfactory results under the stated circumstancesin con nection withroadways or surfaces in which the voids between the bitumen-coated stones I are not filled. and in which the stones are. cemented together solely or principally by their asphalticor bitumen Coatings.

In co-pending applications Nos. 89,762'and There are certain reasons why, for sake of economy, and-a desire to add nothing -organic to the. asphalt, it is desirable to use inorganic substances to efiect this'coa'ting of damp or wet aggregate.

r (I have discovered, therefore, that by the -use of an extremely colloidal clay, such as bentonite, the coating may be effected with- I soaps,sulphonated oils or acid oleates.

stone inthe mixer or pug mill,'and turn it until the bentonite is thoroughly-dispersed From practical trials, I have found that "it takes about 0.15% of a good grade of bento'nite, based upon the weight of the stone. This amount, however, is more or less dependent upon the amount of water in the stone, the amount added will vary in practice from 0.2 per cent to 0.4 per cent, depending upon the charac ter of the stone, and the character of service Application mar August 18,1927. Serial m. 213,973.

, 2% of water by actual test.

'drated lime per ton miX.-

If it'is desirable to add some sandy fines to the mix, they may be added after the asphalt is thoroughly mixed.

In practice, I apply thispowdered c01 loidal'clay '(or bentonite) to damp or wet PATENT orrlcs to'which the road will be subjected. The test referred to was with stone containing p This makes the figure of'0.15% on the weight of the stone 7.5% on the water content of the stone.

After finding that 5% on the weight of the Water was insufficient, I made a series of surface tension tests, and found that 5% was below the surface tension of thewater used, and 7.5% was slightly above it.

It would seem, therefore, that a figure of 7.5% was close to apractical amount to use; the amount addedwill vary in practice from 5% to 8% of themoisturein the stone determined by analysis, and will also be influenced by the character of the service to which the road will be subjected. I, however, claim the right to vary thequantity in accordance with what I find necessary to use to accomplish the desired results.

: After the addition of the bentonite, I proceed in the usual way for making stoneasphalt paving-compositions by the use of a liquefie'r, such as kerosene or naptha, or

suitable mixturesfof these materials, and

prefer to use'hydrated lime immediately after the addition of the melted asphalt.

Because of the chilling effect of the water, it is necessary to have the asphalt well heated. It should be close to 300 F. but not above this figure, as the asphalt, itself, would be endangered by the high heating.

I prefer to use from 5 to 10 pounds of hy- The amount of asphalt used is approxiwith the temperate climates.

Claims: 7 1. The method of preparing a pavlng material from damp stone, which comprises agitating said stone in a mixer and dispersing upon said agitated stone a thin coating of highly colloidal clay, thereafter adding a volatile hydrocarbon to the mass of agitated coated stone and distributing said hydrocarbon over said coated stone, thereafter adding hot asphalt to the mass and continuing the agitation until the asphalt has been distributed over said coated stone.

2. The method of preparing paving material from damp stone, which comprises agitating said stone in a mixer, dispersing highly'colloidal clay upon said agitated stone asa thin coating, said clay constituting avariable amount, and may vary from about 0.2- per cent to per cent ofthe weight of the finished batch of paving material, adding a volatile hydrocarbon to the agitated coated stone, and thereafter adding hot asphalt to the mass, and continuing the agitation until the iasphalt has been distributed over said coated stone.

- The method of preparing paving mateterial from damp stone, which comprises agitating said stone in a mixer and dispersing upon said agitated stone a thin layer of hentonite, thereafter adding a volatile hydrocarbon to the mass of agitated coated stone and distributing said hydrocarbon over said coated stone, thereafter adding hot asphalt to the mass and continuing the agitation until the asphalt has been distributed over said coated stone,

5. The method of preparing paving material from damp stone, which comprises agitating said stone in a mixer, dispersing bentonite, upon said agitated stone as a-thin coating, said bentonite constituting'avariable amount, and may vary from about 0.2 percent to 0.4 percent of the weight of the finished batch of paving material, adding a volatile hydrocarbon to the agitated coated stone, and thereafter adding hot asphalt to the mass,

and continuing the agitation until the asphalt has been distributed over said coated stone.

6. The method of preparing paving mate- "rial from damp stone, which comprises agitating said stone in a mixer, dispersing bentonite upon said agitated stone as a thin coatmg, said bentonite constltutlng a variable amount, and may vary from 5 percent to 8 percent of the weight of the water contained in the stone, adding a volatile hydrocarbon to the agitated coated stone, and thereafter adding hot asphalt to the mass, and continuing the. agitation until the asphalt has been distributed over said coated stone.

7. The method of effecting a bond between asphalt and damp stone, which comprises coating the damp stone with a thin layer of highly colloidal clay, then applying a vola- .tile hydrocarbon to the coated stone, and

finally adding hot asphalt to the treated stone. 8. The method of effecting a bond between asphalt and damp stone, which comprises coatingthe' dampstone with a. thin layer of bentonite, then applying a volatile hydrocarbon to the coated stone, and finally adding hot asphalt to the treated stone.

9. The method of effecting a bond between asphalt and damp stone, which comprises coating the damp stone with a thin layer of bentonite, then applyingkerosene to the coated stone, and finally adding hot asphalt to'the treated stone.

10. The method of preparing a paving material from damp stone, which comprises agi tating said stone in a mixer and dispersing upon said agitated stone a'thin layer of bentonite, thereafter adding kerosene to the mass r of agitated'coated'stone and distributing said kerosene over said coated stone, thereafter adding hot asphalt to the mass'and continuing the agitation until the asphalt has been distributed over said coated stone.

11-.'The method of preparing paving material from damp stone, which comprises agitating said stone in a mixer, dispersing bentonite upon said agitated stone as a thin coating, said bentonite constituting a variable amount, and may vary from 0.2 percent to 0A percent of the weight of the finished batch of paving material, adding kerosene to the agitated coated stone, and thereafter ad ding hot asphalt to the mass, and continuing the agitation until the asphalt has been distributed over said coated stone.

12. The method of preparingpaving material from damp stone, which comprises agitating said stone in a mixer, dispersing bentonite upon said agitated stone as a thin coating, said bentonite constituting a variable amount, and may vary from five percent to eight per cent of the weight of the-water contained in the stone, adding kerosene to the agitated coated stone, and thereafter adding hot asphalt to the mass and continuing the agitation until the asphalt has been distributed over said coated stone.

In testimony whereof I afiix my signature.

SAMUEL S. SADTLER. 

